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Wednesday, January 18, 2012

Heuristics and Cognitive Biases in Decision Making During Clinical Emergencies

When faced with a potential clinical emergency situation, physicians are often expected to make diagnostic decisions within a limited time frame. A delayed decision, albeit an accurate one, is a futile decision if the patient deteriorates. Therefore, as almost always, such urgent decisions have to be made with some degree of uncertainty. This is especially so in an environment like the emergency department.


Physicians in emergency department make many decisions in the course of a working shift, some of which can have high consequences. Furthermore, emergency departments often have unpredictable and variable patient volume load as well as clinical acuity. Given the unfavorable nature of such environment, emergency department is often a place that is vulnerable to error. Under such circumstances, a physician in emergency situation often employs a compendium of heuristics (Croskerry et al, 2009).

Heuristics are mental shortcuts or “rules of thumb” or “gut-feeling” (Croskerry et al, 2009) used to assist a physician to rapidly make decisions without formal analysis. It is largely a form of gestalt pattern recognition that is intuitive and its accuracy is dependent on the experience of the physician. Two heuristics that are considered essential when faced with an emergency situation are the “rule-out-worst-case-scenario” and the sick/not sick dichotomy (Croskerry et al, 2009).

When properly applied, these heuristics can be beneficial, but they will occasionally spell disaster when a number of cognitive biases are overlooked. Among the important cognitive biases in clinical medicine are:
  1. availability bias – it refers to our tendency to judge things as being more likely, or frequently occurring, if they readily come to mind. Therefore, a recent experience with a disease might inflate our likelihood to diagnose the patient with this disease
  2. anchoring – it refers to out tendency to perceptually fixate on to the salient features in the patient’s initial presentation at an early point of the diagnostic process and failing to adjust our initial impression even in the light of later information. 
  3. confirmation bias - it refers to our tendency to look for confirming evidence to support the diagnosis we are “anchoring” to, while downplaying, or ignoring or not actively seeking evidences that point to the contrary. 
  4. search satisficing – it refers to our tendency to stop looking for alternate or even coexisting diagnoses when we have found one. A classic example of this is the tendency of the physician to call off the search for a second fracture once he thinks he is “sufficiently satisfied” with finding the first fracture (Croskerry et al, 2009).
Actually there is a long list of cognitive biases (but the four listed are the common ones in emergency medicine) taken from a book written by Baron, J. Professor Baron has done significant works in this area of judgment, decision making and cognitive biases (not specifically pertaining to emergency medicine, but in general). Check out his website for more resources.  Also see the list of cognitive biases in wikipedia.


Ultimately however, the application of heuristics in clinical medicine is inevitable, particularly in emergency situations where every minute counts. For example, in a case of witnessed ventricular fibrillation (VF), immediate step of resuscitation and defibrillation is called for. In such cases, the physician must be trained with the ability for gestalt pattern recognition of VF even within the ‘blink’ of an eye. No time should be lost in searching for the underlying causes of the ventricular fibrillation.

The question, therefore, is not whether the use of heuristics can be minimized or not. The question is how we can temper heuristics with de-biasing strategies so that a more calibrated and balanced diagnostic decision could be made. Such de-biasing strategies are often called cognitive forcing strategies. These are deliberate, systematic self-regulatory cognitive mechanisms to provide a check and balance to minimize biases.
One form of cognitive forcing strategy often used is known as the metacognition. It describes an individual’s ability to stand apart from his own thinking in order to be aware of his own preferred learning approaches and ultimately to manipulate his own cognitive processes to his own advantages. In short, metacognition is “thinking about thinking.” It allows one to ask questions like: “How well did I do?” “What could I have done it differently if I am given a chance again?”, etc.

Therefore, making a timely, well-calibrated decision in an emergency situation is a critical thinking skill that should be inculcated in every physician. In fact, critical thinking in emergency medicine is defined as “the intellectually disciplined process of actively and skillfully conceptualizing, applying, analyzing, synthesizing, and/or evaluating information gathered from, or generated by, observation, experience, reflection, reasoning or communication, as a guide to belief or action” (Croskerry et al, 2009).

It is often assumed that every medical student would have developed this critical thinking skill by the time they have graduated from medical schools and would continue to further mature their cognitive process when they start working. After all, university graduates are expected to have a scholarly attitude towards knowledge and university is expected to be more than just a center for knowledge transmission (Biggs & Tang, 2007).

Unfortunately, within the specific context of undergraduate medical curriculum, the expectation that medical students will eventually develop matured critical thinking skill is largely empirical and yet to be explored or formally studied.

Furthermore, studies done in other field of tertiary education show potential cultural influence on critical thinking skill acquisition among undergraduate students. In fact, these differences have led to discussions and debates about the appropriateness of applying Western pedagogy for Asian students.

From some of these studies, it was shown that Asian university students are less likely to engage in critical thinking compared to their Western counterparts. In many Asian countries, the teaching and learning activities are often exam-driven in large-sized classrooms and structured around the goal of succeeding in examinations (Biggs & Watkins, 2001). Furthermore, Asian learners are usually perceived as silent, passive, uncritical and compliant rote-learners who rely on memorization (Biggs and Watkins, 1996); although paradoxically, despite of this rote-based learning strategy, Asian learners have often been found to outperform their Western counterparts (Biggs and Watkins, 2001).

Even within Malaysia, our tertiary students are found to be rather reserved about voicing their own opinions. One of these culturally influenced perceptual learning styles is their preference to be neutral, to “save face” as well as to adopt a conservative rather than confrontational approach (Yong, 2010).


The questions therefore are:

What is the preferred learning style of our medical students – passive rote learning or active engagement in discussion and challenges? And is this preference culturally influenced?

Does this pedagogy preference translate into the way our house officers deal with their seniors with they have a different opinion compared to their seniors? Do they passively comply with following orders or do they actively engage in discussion with them?

How does that affect our house officers when they face with a decision-making situation in clinical emergencies? Do they passively leave the decision to their seniors? What is their risk preference – they do prefer to choose a riskier alternative to “do something for the patient” (much like a gambling paradigm) or do they rather choose a more conservative approach of “wait and see”?

Do our house officers, therefore, perceive a chasm in the acquisition of the decision-making skill in clinical emergencies during their transition from being a student in medical school to being a newly qualified doctor? In other words, do they perceive that their medical schools do not prepare them enough for critical thinking and decision-making skills?
Professor Croskerry has written a substantial number of articles and books on these topics. Click here to download an article by Prof Croskerry.

References:

Biggs, J. B. & Watkins, D. A. (1996) In Asian Contributions to Cross-Cultural Psychology (Eds, Paudey, J., Sinha, D. and Bhawuk, D. P.) Sage Publication, New Delhi.

Biggs, J. B. & Watkins, D. A. (2001) In Teaching the Chinese Learner: Psychological and Pedagogical Perspectives(Eds, Watkins, D. A. and Biggs, J. B.) Comparative Education Research Centre, the University of Hong Kong, Hong Kong, China, pp. 277-300.

Biggs, J. B., & Tang, C. (2007). Teaching for Quality Learning at University: What the Students Does (3rd ed.). New York, NY: Open University Press.

Croskerry, P. (2009). A universal model of diagnostic reasoning. Acad Med, 84(8), 1022-8.

Croskerry, P., Cosby, K., Schenkel, S. M. & Wears, R. L. (2009) Patient Safety in Emergency Medicine, Wolters Kluwer Health/Lippincott Williams & Wilkins, Philadelphia.

Yong, F. L. (2010). A Study on the Cultural Values, Perceptual Learning Styles, and Attitudes Toward Oracy Skills of Malaysian Tertiary Students. Europ. J. Soc. Sci., 13, 478-92.

2 comments:

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